hey guys, this is what i did to play praetorians and it worked,so if u having a problem then just do that and i'll think you'll be safe,
ok quick instructions:
my computer------> control panel------->windows firewall-------> untick "dont allow exceptions"------->then click ok .
click on start------->run-------> write "cmd.exe" then press ok------->write "ipconfig" then press enter-------> then copy default gateway address number(ip) and paste it in ur browser(example: 192.168.1.1 urs could be different)------->and press enter .(if it asks u for a username and pass then look at ur router should be written on it or on its box)
you will now see specifications and some info abt ur router ------->add ports------->add port 2300(start) to 2400(end) choose both proctocols(both tcp and UDP)------->add port 47624(start) to 47624(end)protocol UDP only -------> save

To see wich games are available to be played open praetorians then multiplayer then choose the choice wich have an ip number who starts with a "5" and click ok then you will see list of availble or currently open games or you can create a game urself.. (no need to write host ip or that thing.. just leave it blank)

my nickname in hamachi is "US forces",GOOD LUCK AND LET ME KNOW IF U HAVE ANY PROBLEM!